Conventionally, a light sensor of several integrated sensors is proposed by, for example, Patent Literature 1, Specifically, a configuration in which a rain sensor is integrated with an ambient light sensor is proposed. The light sensor is mounted to the windshield of a vehicle. Then, the rain sensor measures changes in the intensity of light by detecting changes in refractive property caused by raindrops adhering to the windshield. In addition, the ambient light sensor detects the brightness of ambient light irradiated from outside through the windshield.